How do you pass options to the env preset when using babel-node through the command line? I've looked through the docs but was unable to find how to configure the babel-node env preset.
What I'm trying to target the current version of node installed on my machine. The equivalent with a .babelrc file would be
{
"presets": [
["env", {
"targets": {
"node": "current"
}
}]
]
}
Thanks!
You can use inline --presets flag.
For Example:
babel-node index.js --presets=env
Related
I'm faced with a problem with my API in Heroku. I have a Node JS API, built with Typescript and hosted in Heroku. Everything looks correct when I try to execute the local script and build the script, but when I need to run the start script, things don't work.
My configurations are:
Node: v18.12.1
NPM: v8.19.2
I have some scripts to transpile .ts files to .js files with babel
"build": "babel src --extensions \".js,.ts\" --out-dir dist --copy-files",
"dev:server": "ts-node-dev -r tsconfig-paths/register --inspect --transpile-only --ignore-watch node_modules src/shared/infra/http/server.ts",
"start": "node dist/shared/infra/http/server.js"
When I execute dev:server and build script, everything runs with success, but when I run the start script, I receive this error:
enter image description here
I checked some points, like my tsconfig.json and my babel.config, but everything looks correct.
module.exports = {
presets: [
['#babel/preset-env', { targets: { node: 'current' } }],
'#babel/preset-typescript',
],
plugins: [
[
'module-resolver',
{
alias: {
'#modules': './src/modules',
'#config': './src/config',
'#shared': './src/shared',
},
},
],
'babel-plugin-transform-typescript-metadata',
['#babel/plugin-proposal-decorators', { legacy: true }],
['#babel/plugin-proposal-class-properties', { loose: true }],
[
'const-enum',
{
transform: 'removeConst',
},
],
],
};
Because of it, when I deploy API in Heroku, I recive this error:
enter image description here.
I don't have an idea why this occur, because about 1 month ago the API was running perfectly on Heroku production instance.
I appreciate it if anyone can help and give me some tips, about this problem.
What I tried
Check and change my npm and node versions
Check babel confgs
Add "type":"module"in my packages.json
How do I inject my environment variable into the final build that gets published to npm?
I'm using the dotenv package and that works great locally. However when I do npm publish, the env variable is gone since it just runs the file in the main property of the package.json.
Some relevant fields from package json:
"main": "./lib/index.js",
"typings": "./lib/index.d.ts",
"files": [
"lib",
".env"
],
"scripts": {
"start" : "tsc && node -r dotenv/config ./lib/index.js"
},
"bin" : {
"run-app" : "./lib/index.js"
},
"dependencies": {
"dotenv": "^8.2.0",
}
.gitignore:
# OSX
.DS_Store
node_modules
notes.MD
lib
.env
I tried to inject my env variable by passing it to my start script and also call the .config() method on dotenv inside the code. Either way the env variable ends up undefined when running my package using npx.
What am I doing wrong?
babel-node --experimental-worker app.js
Using this command for starting my project in development mode. Output is:
error: unknown option--experimental-worker'
config .babelrc:
{ "presets": [ ["env", { "targets": { "node": "current" } }], "stage-0", "flow" ], "plugins": [ "transform-decorators-legacy", "transform-flow-strip-types" ] }
This flag is needed to use worker threads. Using babel 6.26
I just ran into this today and replied to the issue on GitHub here. I've pasted my fix below:
I was using Nodemon, and it turns out that there's an option to
include environment variables as NODE_OPTIONS in the nodemon.json
file. This did the trick for me:
{
"watch": ["server"],
"ext": "js",
"env": {
"NODE_OPTIONS": "--experimental-worker"
},
"exec": "babel-node server/server.js"
}
How to integrate Nodemon + worker_threads into a normal NodeJS app:
Set up Nodemon
Add a nodemon.json file to the root folder (example here)
Add this to nodemon.json:
"env": {
"NODE_OPTIONS": "--experimental-worker"
}
If you're setting up Nodemon for the first time, I found
this tutorial very helpful.
The idea is to split your command into two phases:
Phase 1:
babel app.js --out-file app-compiled.js
And phase 2:
node --experimental-worker app-compiled.js
In npm scripts you can then combine the two:
"scripts": {
"pre-build": "babel ./app.js --out-file ./app-compiled.js",
"serve": "yarn pre-build && node --experimental-worker ./app-compiled.js"
}
It not actually for me already. I am refused to use nodemon and run my code with command
node --experimental-worker -r babel-register $NODE_DEBUG_OPTION app.js
It`s help me use exeprimental workers with babel, but with nodemon - not
I am using the dotenv package to inject environment variables to my OS which I can specify by calling the following:
node -r dotenv/config dist/app.js
How can I run the same command from launch.json? Currently I have the following but it doesn't load the dotenv package
"program": "${workspaceFolder}\\dist\\app.js",
"args": [
"-r dotenv/config"
],
Try using this as one of the keys instead of args:
"runtimeArgs": [
"-r",
"dotenv/config"
]
I have this .babelrc file:
{
"presets": ["env"],
"outDir":"target",
"include":[
"src/**/*.js"
],
"ignore": []
}
I run babel -w and I get this error message:
--watch requires --out-file or --out-dir. --watch requires filenames
do I need to specify more options at the command line or is there something I can add to my .babelrc file?
There is no way to configure this in your .babelrc. But you could add something like this to the scripts section of your package.json:
"scripts": {
"watch": "babel --watch src --out-dir dist"
}
Then you can just run npm run watch from the root of that project.
If you want to execute your project each time you compile, you can use babel-watch.